Dumbbell rack assembly



FIG. 1 is a perspective view of a dumbbell rack assembly showing my new design, with broken line representations of features for the dumbbell rack assembly forming no part of the claimed design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a side view thereof;

FIG. 5 is a side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken line showings of portions of the dumbbell rack assembly in FIGS. 1-7 are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a dumbbell rack assembly, as shown and described. 